Shared power, not White House domination of Congress, appears to be the pattern emerging in the Reagan administration's dealings with Capitol Hill. Rumblings of dissent from within the halls of Congress could be heard distinctly at the other end of Pennsylvania Avenue in recent days over the White House's social security and tax plans. The warning: Do not provoke the legislators.

Although Congress appeared to yield docilely to White House leadership on the budget issue, the legislative branch remains a formidable giant that could rise to thwart White House hopes.

President Reagan's continued ability to lead lawmakers depends largely on his popularity and on his ability to maintain the sense of shared electoral accountability between President and Congress dramatized in the 1980 election for the first time since Lyndon Johnson's 1964 sweep.

With additional budget, war powers, and other resources acquired since 1973, Congress is equipped to do battle with a modern president who encroaches on its turf, congressional experts say.

"It's possible for Congress to be powerful, assertive, and yet cooperative with the President, if everything comes together as it is right now," says congressional affairs expert Thomas Mann. "What we've seen with Reagan and Congress is not the decline of Congress, but a sharing of power."

Congress is quietly asserting itself in writing tax policy. The four tax-writing powers on Capitol Hill -- Sen. Bob Dole (R) of Kansas, Sen. Russell B. Long (D) of Louisiana, Rep. Dan Rostenkowski (D) of Illinois, and Rep. Barber B. Conable Jr. (R) of New York -- met earlier this week to sort out differences between the White House and Congress. Members of the Senate and House sharply warned the administration it was veering dangerously from the public's will with its social security reforms and that Congress would not follow.

Nor is Congress rolling over on foreign policy. The Senate is giving the White House a hard time on the President's nomination of Ernest W. Lefever as assistant secretary of state for human rights and humanitarian affairs. The House is sticking to the Clark amendment -- passed in 1975 to stop covert US support of right-wing forces opposing Marxists in Angola -- despite the Reagan administration's request to repeal it.

"On El Salvador, the sale of AWACS to the Saudis, Congress has no intention of rolling over," Mann says.

A well-functioning Congress needs an assertive executive leadership, Mann says. In many cases, Reagan's ability to mobilize public opinion could make it easier for Congress to do its job. On the social security issue, for example, Congress already has been studying the system's long-range financing problems.

"With Reagan, Congress seems to have reverted to its earlier attitude of let the President lead," says James Sundquist, author of a Brookings Institution study, "The Decline and Resurgence of Congress," to be published in August.

This acquiescence began in 1921, when Congress yielded resposibility for drafting the budget to the White House, and continued for some 50 years. Congress's comeback began in reaction to Nixon's impoundment of federal funds, in effect unilaterally repealing laws, Mr. Sundquist says. Nixon was seen as carrying on a "unilateral war" in Southeast Asia. He set up a reorganization plan even after Congress rejected it.

Congress almost impeached Nixon and passed the War Power Act to prevent presidents from conducting war without congressional confirmation within 48 hours. It passed the Congressional Budget Act, giving Congress the last word in cutting budgets -- and, ironically, the budget machinery now enabling President Reagan to get action on his budget plan. Congress reasserted itself in foreign policy with more congressional oversight hearings. Bigger staffs gave Congress their own data and analytical resources to counter the White House.

At the moment, Congress seems to prefer letting the President take the lead again, contenting itself with making changes at the margins, or cooperating with executive wishes.

"We had this phenomenon in 1913, when Wilson's party followed him almost totally for two years," Sundquist says. "Roosevelt had five years -- before he ran into the Supreme Court-packing issue. Johnson had only eight months, until the riots in Watts in August 1965 put a stop to Great Society legislation. Only model cities and fair housing legislation passed after Watts."

Roosevelt prolonged his mastery of Congress by drawing Republican to Democratic ranks, Sundquist says. Republicans in 1932 fought the Roosevelt program root and branch, to their peril. With Reagan, Democrats are "rolling with the punch, modifying at the edges," and so may escape the rout the Republicans endured by resisting the New Deal tide of the 1930s.